High-temperature redistribution of cation vacancies and irreversible magnetic transitions in the Fe1-xS nanodisks observed by the Mossbauer spectroscopy and magnetic measurements

作者：Lyubutin Igor S^*; Lin Chun Rong; Lu Shin Zong; Siao Yu Jhan; Korzhetskiy Yuriy V; Dmitrieva Tatyana V; Dubinskaya Yuliya L; Pokatilov Vyacheslav S; Konovalova Anastasiya O

来源：Journal of Nanoparticle Research, 2011, 13(10): 5507-5517.

DOI：10.1007/s11051-011-0538-1

• Nanosheets
• Pyrrhotite
• Vacancy distribution
• Mossbauer effect

The hexagonal pyrrhotite Fe1-x S nanodisks with the NiAs-type structure were synthesized by thermal decomposition of ferrous chloride and thiourea in oleylamine. The Mossbauer spectroscopy and magnetic measurements data indicate that a mixture of antiferromagnetic (AFM) and ferrimagnetic (FRM) phases with the NC (N a parts per thousand yen 3) and 2C-type superstructures is present in the Fe1-x S compound at temperatures between 80 K and N,el temperature T (N). At T < 370 K, the AFM phase prevails over the FRM phase. At T > 370 K, a redistribution of iron vacancies takes place, and the vacancy ordering transforms from the NC (N a parts per thousand yen 3) to 2C-type which essentially increases the magnetization with maximum value at 470 K. Heating the sample above the N,el temperature 565 K leads to a random distribution of vacancies, and this state is quenched upon subsequent cooling of the sample to 300 K. This gives rise to a pure AFM structure with a zero magnetic moment due to a total compensation of the moments in neighboring iron layers. Thus, the high-temperature redistribution of cation vacancies leads to irreversible magnetic transformations in the Fe1-x S nanoparticles.

• 出版日期2011-10